X OF MATHEMATICS
Poincaie's busy life was tranquil and happy. Honours were
showered upon him by all the leading societies of the world, and
in 1906, at the age of fifty-two, he achieved the highest distinc-
tion possible to a French scientist, the Presidency of the
Academy of Sciences. None of all this inflated his ego, for
Poincare was truly humble and unaffectedly simple, Ke knev
of course that he was without a close rival in the days of his
maturity, but he could also say without a trace of affectation
that he knew nothing compared to what is to be known. He
was happily married and had a son and three daughters in
whom he took much pleasure, especially when they were chil-
dren. His wife was a great-granddaughter of fitienne-Geonroy
Saint-Hilaire, remembered as the antagonist of that pugnacious
comparative anatomist Cuvier. One of Poineare''s passions was
symphonic music.
At the International Mathematical Congress of 1908, held at
Rome, Poincare was prevented by illness from reading his
stimulating (if premature) address on The Future of Mathe-
matical Physics. His trouble was hypertrophy of the prostate,
which was relieved by the Italian surgeons, and it was thought
that he was permanently cured. On his return to Paris he
resumed his work as energetically as ever. But in 1911 he began
to have presentiments that he might not live long, and on
9 December wrote asking the editor of a mathematical journal
whether he would accept an unfinished memoir — contrary to
the usual custom - on a problem which Poincare considered of
the highest importance: '... at my age, I may not be able to
solve it, and the results obtained, susceptible of putting re-
searchers on a new and unexpected path, seem to me too full of
promise, in spite of the deceptions they have caused me, that I
should resign myself to sacrificing them. ..* ' He had spent the
better part of two fruitless years trying to overcome his
difficulties.
A proof of the theorem which he conjectured would have
enabled him to make a striking advance in the problem of three
bodies; in particular it would have permitted him to prove the
existence of an uinnity of periodic solutions in cases more
general than those hitherto considered. The desired proof was
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